1. Jean L Pelegrino, How money came into being, www.shvoong.com/ books/1715093-money
2. Ludwig von Mises, The Theory of Money and Credit, Yale Univ. Press, 1953.
3. http://en.wikipedia.org/wiki/History_of_banking
4. “rch.microsoft.com/en-us/um/redmond/groups/crypto/ecash.aspx”
5. Edward Hadas, Prediction: bitcoin is doomed to fail, NY Times, Dec, 2013.